Simon Hall: his previous appeal was dismissed in 2004. He insists he was out drinking at the time Joan Albert was murdered. Photograph: Suffolk Police/PA

The appeal court today reserved judgment in the case of Simon Hall, 33, who is serving a life sentence for the murder of an elderly woman nine years ago.

No date was given for a decision to be announced by Lord Justice Pitchford, Mrs Justice Dobbs and Mr Justice Kenneth Parker, but it is not expected before Christmas.

"I'm obviously gutted," said Hall's wife, Stephanie. "He's 200% innocent and he's still in jail because two forensic experts can't agree on the fibres. It will mean another Christmas alone and I'm furious because I know the real killers are walking the streets."

This week's three-day appeal threw up sharp differences between forensic scientists, one testifying for the defence and two for the prosecution, centring on the examination of fibres at the murder scene and at Hall's home.

Tiernan Coyle, for the defence, said the fibres found at the murder scene differed consistently from those found at addresses and a car connected to Hall. Two forensic scientists called by the government, however, questioned the appropriateness of Coyle's method, called the first derivative technique, which is used to statistically analyse the presence of chemicals in fibres.

Ray Palmer told the court that the method exaggerated what small differences there were between the two sets of fibres and Roger Robson asserted that Palmer's approach was "safer".

Legal experts said it was no surprise that the judges reserved judgment as it was such a complex case. "You had three highly credible forensic scientists, all very respectful of each other, with a preference for their own methods," said Dr Michael Naughton of the University of Bristol Innocence Project (UoBIP). "It's a very tricky case for the judges and will be important for the future use of fibre evidence."

Hall, whose previous appeal against conviction was dismissed in 2004, had his case referred to the court of appeal by the Criminal Cases Review Commission, an independent body which investigates possible miscarriages of justice, after submissions from the Bristol innocence project. The UoBIP involves students working on real cases concerning long-term prisoners who maintain their innocence but have exhausted the criminal appeals system and have no legal aid.

"At the very least, the judges should order a retrial," said Naughton, "but if they have the courage, they should quash the conviction."

Hall was convicted in 2003 of the murder of Joan Albert, a 79-year-old widow who was stabbed during a break-in at her home. Hall, a power company office worker from Ipswich, was 25 when he was jailed for life at Norwich crown court.

Albert's body was found in the hallway of her home in Capel St Mary, near Ipswich, in December 2001. She had been stabbed five times. Prosecutors said Hall broke into her home with the intention of stealing and attacked the pensioner when she disturbed him. Hall, who denied murder and has continued to protest his innocence, said he was out drinking at the time of the crime.

The appeal judges were urged to rule that the conviction was unsafe in the light of the "fresh" scientific evidence relating to fibres.